The invention relates to a method and apparatus for producing exact length skip perforations in constant and exact registration with a paper web being processed, on-demand from external signals (typically from a computer controller). While there is a significant body of prior art pertaining to what is commonly known in the industry as "quick skip" or "jump" perforating in which perforations are selectively applied to portions of a moving web (typically a web of business forms), there is dearth of prior art that provides exact accuracy of the perforating action in combination with on-demand control.
There are two basic principles of prior art perforating apparatus. The first is either a driven circumferentially sized partial/interrupted anvil, or perforating wheel coacting against either a full circumference perforator wheel or anvil cylinder. The second is a cam operated rotary perforating wheel operating against a hardened anvil cylinder. The cam operated device may be easily adapted to on-demand printing, however cam operated devices are normally significantly speed-limited, and are prone to premature wear due to impact forces. Also exact on/off locations for the perforations are extremely difficult to obtain using that system. Therefore according to the present invention a perf wheel/anvil system is utilized which is configured and operated in a novel manner so as to get exact length skip perforations in constant and exact registration with a paper web being processed on-demand from external signals, with long life. The apparatus and method according to the invention are also relatively simple to construct and utilize.
According to one aspect of the present invention an on-demand exact registration form web perforating apparatus is provided comprising the following components: Means for moving a form web in a predetermined path in a first direction. First and second rotatable substantially continuous circumference perforator wheels mounted on substantially stationary axes spaced from each other along the predetermined path, and in alignment with each other along the path in the first direction. First and second anvil cylinders spaced from each other along the predetermined path, each comprising: an interrupted circumference including a raised circumferential portion and a depressed circumferential portion; and a movable axis about which the cylinder rotates. Means for rotating the anvil cylinders about the axes synchronously with the web moving means. And, means for selectively moving each of the axes of the anvil cylinders toward and away from the perforator wheels from a first position in which the entire circumference of the anvil cylinder is spaced from the web and does not cooperate with a the perforator wheel, to a second position in which the anvil cylinder circumference raised portion may engage the web and cooperate with a the perforator wheel to effect perforation of the web substantially parallel to the first direction.
The form web typically comprises a plurality of business forms each having a predetermined length x along the predetermined path, and the perforator wheels each have a circumferential point closest to an anvil cylinder, the circumferential points spaced from each other along the predetermined path a distance yx, where y is a positive whole number (typically 1 or 2). The raised portion of each anvil cylinder and an imaginary continuation thereof over the depressed portion typically has a circumference of 2x.
The selectively moving means may comprise any conventional apparatus for moving the cylinders into operative association with the perforated wheels while not interfering with drive of the cylinders. Preferably the selectively moving means move the cylinders toward the perforator wheels so that the centerlines of the anvil cylinders and the centerlines of the perforator wheels are aligned and perpendicular to the web in the second position. In the preferred embodiment of the invention the anvil cylinders are mounted in eccentric bearing housings, and the selectively moving means moves the axes of the anvil cylinders toward and away from the perforator wheels by rotating the eccentric bearing housings so that the eccentric rotation of the bearing housings effects movement between the first and second positions. The means for rotating the eccentric bearing housings may comprise any conventional structure capable of performing that function, such as a linear actuator (such as a high performance air cylinder connected by a crank arm to the housing), or a rotary actuator, stepper motor, or servo motor, the latter two particularly for higher speed operation. Typically the means for rotating the eccentric bearing housings rotates the housings between about 15-25.degree. (preferably about 20.degree.) between the first and second positions and obtain a clearance between the perforator wheel and the raised portion of the interrupted anvil cylinder, when in the first position, of about 0.007 inches.
The means for moving the form web in a predetermined path in a first direction may comprise any conventional web driving mechanism, such as powered drive rollers, take-up shafts or cylinders, or the like. In the preferred embodiment according to the invention the web moving means includes at least first, second and third guide rollers, the anchor cylinders located between the first and third guide rollers in the predetermined path, and a second guide roller located between the second cylinders in the predetermined path. The guide rollers may be positioned with respect to the perforator wheels so that the web is substantially tangent to the perforator wheels when engaging the guide rollers. Since the perforator wheels are not driven, but rather are idler wheels, no perforating action takes place unless the raised portion of the anvil cylinder engages the opposite surface of the web from the perforator wheel. A first plane passes between the centers of the first and third guide rollers that is parallel to a second plane passing between the axes of the perforator wheels, and the first and second planes are spaced a first distance. A third plane passing through the center of the second roller parallel to the first plane is spaced from the second plane a second distance which is less than the first distance, i.e. so that the predetermined path is slightly V-shaped at the perforation area.
The axes of the perforator cylinders are substantially stationary--but can be adjusted to allow minor adjustment of the positions of the perforator wheels with respect to the predetermined path, and thus to provide wheel pressure adjustment.
Another perforator wheel may be mounted on a common axes with each of the first and second wheels, spaced from the first and second wheels in a second direction substantially transverse to the first direction.
According to another aspect of the present invention apparatus for perforating a form web is provided comprising the following components: A predetermined path of movement of a form web. A rotatable substantially continuous circumference perforator wheel mounted on a substantially stationary axis on a first side of said predetermined path. An anvil cylinder comprising: an interrupted circumference including a raised portion and a depressed portion; and a movable axis about which the cylinder rotates, the anvil cylinder mounted in an eccentric bearing housing and the movable axis disposed on a second side of the predetermined path, opposite the first side. Means for rotating the anvil cylinders about the axis. And, means for selectively moving the axis of the anvil cylinder toward and away from the perforator wheel from a first position in which the entire circumference of the anvil cylinder is spaced from the predetermined path and does not cooperate with a the perforator wheel, to a second position in which the anvil cylinder circumference raised portion may intersect the predetermined path and engage a web moving in the path and cooperate with the perforator wheel to effect perforation of the web parallel to the first direction, the selectively moving means comprising means for rotating the eccentric bearing housings so that eccentric rotation of the bearing housings effects movement between the first and second positions.
The details of the means for rotating the eccentric bearing housings, and the like, are preferably as described earlier for the first aspect of the invention.
According to another aspect of the present invention a method of perforating a web of business forms, utilizing first and second substantially continuous circumference perforator wheels operatively spaced from each other along a predetermined web path, and first and second anvil cylinders also operatively spaced from each other along the web path and each having a raised circumferential portion and a depressed circumferential portion, the raised portions for cooperating with the perforator wheels to perforate the web is provided. The method preferably comprises the following steps: (a) Moving the web in a first direction along the predetermined web path. (b) Selectively automatically moving the anvil cylinders from a first position in which no circumferential portion of the anvil cylinders engages the web, to a second position in which the raised circumferential portions of the cylinders may engage the web and cooperate with the perforator wheels to effect perforation of the web parallel to the first direction. (c) Rotating the anvil cylinders so that a point on the circumference thereof moves tangentially in the first direction synchronously with the movement of the web in the first direction. And, (d) selectively automatically moving the anvil cylinders from the second position to the first position thereof.
The wheels and cylinders are typically spaced from each other along the predetermined path a distance yx where x is the length of a form of the web along the predetermined path and y is the positive whole number, and the circumference of each of the raised portions of the anvil cylinder and an imaginary extension thereof overlying the depressed portions is equal to 2x; and then steps (a)-(d) are practiced to perforate each even form in the web with the first wheel and cylinder, and perforate each odd form in the web with the second wheel and cylinder. Steps (b) and (d) are preferably practiced so as to move the centerline of each anvil cylinder and the centerline of its associated perforator wheel into alignment and substantially perpendicular to the web; and in response to electrical signals from a computer control (such as a Moore XL Data System, available from Moore U.S.A., Inc. of Lake Forest, Ill.).
It is the primary object of the present invention to provide effective exact length skip perforations in constant and exact registration with a paper web being processed, on-demand from external signals, and with a long life of the components utilized. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.